| Author |
Message |
    
Joewilson
Tinkerer
Username: Joewilson
Post Number: 4
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 09, 2010 - 06:55 pm: | 
|
Alright so i've got a Nikkor-S 50mm 1.4 here, the blades are perfect but maybe the spring is the problem?
What happens is that if it sits for a while it gets a little slugish and inacurate, it sometimes wont stop all the way down. If i work the aperture lever back and forth over and over it tends to loosen up, but when i let it sit for while the problem comes back again.
I've taken it apart and can't really see anything wrong back there, or anything that would be causing friction. What really stumps me is that it isn't a constant problem.
Perhaps the spring just isn't strong enough to pull it all the way back? In that case, can anyone give me some advice on where i can get a new spring, or if doing something like cutting a small bit off of the spring to increase the tension is a good idea?
Thanks! |
Brcamera
Tinkerer
Username: Brcamera
Post Number: 2
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 10, 2010 - 01:52 am: |
|
The fact that it gets sluggish after resting for a while tells me that it most likely is oil residue.
If you are certain that the blades are totally free of oil, then I would check the blade operating ring for oil residue. It would be a rare case where the problem is a weak spring, normally the issue is some slight binding caused by wear or oil. |
Joewilson
Tinkerer
Username: Joewilson
Post Number: 5
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 10, 2010 - 09:35 am: |
|
Thanks, is it possible there could be some oil hidden away on an area of the blades that isn't easily visible? When i look at the blades stopped down all the way from the front and back they appear very clean, that is all i am going on when i say that i don't think they are the issue. |
Brcamera
Tinkerer
Username: Brcamera
Post Number: 4
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 10, 2010 - 10:13 am: |
|
Yes, there certainly can be oil on the blades that is hidden from casual view. There can be oil on the blade where the blade pivot contacts the mechanism and if not there, then the diaphragm control ring assembly. It can take very little oil to slow down the blades. I have had hundreds of lenses on my repair bench and your description of the issue really sounds like oil residue. The first thing I would do is remove the blades and operating rings and completely clean them.
Bill |
Joewilson
Tinkerer
Username: Joewilson
Post Number: 6
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 10, 2010 - 12:10 pm: |
|
Ok thanks, in that case does anyone have any advice on getting access to the blades on this particular lens? Should i be going in from the front or the back?
Going in through the back i can easily remove the mount ring assembly, and unscrew the rear element but i am stumped after that point.
From the front i dont really see anywhere to start.
Sorry if these are pretty stupid questions, i'm a novice here and appreciate any help you can give!
PS: I can add some photos if it will be helpful |
